Abrasive Article

ABSTRACT

The disclosure relates to an abrasive article that includes a fabric substrate comprising strands forming first void spaces between the strands. The fabric substrate comprising an abrasive side and an attachment side. The abrasive article also includes a coating on the attachment side. The abrasive article also includes a make layer joined to the fabric substrate on the abrasive side. The abrasive article also includes abrasive particles joined to the make layer. The abrasive article also includes a plurality of second void spaces extending through the make layer coinciding with first void spaces in the fabric substrate. The coating on the fabric substrate is both hydrophobic and lipophobic. The attachment side of the fabric substrate is substantially free of make layer.

BACKGROUND

It is very common for dry sanding operations to generate a significantamount of airborne dust. To minimize this airborne dust, it is common touse abrasive discs on a tool while vacuum is drawn through the abrasivedisc, from the abrasive side through the backside of the disc, and intoa dust-collection system. For this purpose, many abrasives are availablewith holes converted into them, to facilitate this dust extraction. Asan alternative to converting dust-extraction holes into abrasive discs,commercial products exist in which the abrasive is coated onto fibers ofa net-type knit backing in which loops are knit into the backside of theabrasive article. The loops serve as the loop-portion of a hook-and-loopattachment system for attachment to a tool. Net type products are knownto provide superior dust extraction and/or anti-loading properties, whenused with substrates known to severely load traditional abrasives.However, cut and/or life performance are still lacking. Thus, there is aneed for a net type product that provides enhanced cut and/or lifeperformance while demonstrating superior dust extraction.

SUMMARY

A disclosure relates to an abrasive article that includes a fabricsubstrate comprising strands forming first void spaces between thestrands. The fabric substrate comprising an abrasive side and anattachment side. The abrasive article also includes a coating on theattachment side. The abrasive article also includes a make layer joinedto the fabric substrate on the abrasive side. The abrasive article alsoincludes abrasive particles joined to the make layer. The abrasivearticle also includes a plurality of second void spaces extendingthrough the make layer coinciding with first void spaces in the fabricsubstrate. The coating on the fabric substrate is both hydrophobic andlipophobic. The attachment side of the fabric substrate is substantiallyfree of make layer.

The above Summary is not intended to describe each illustratedembodiment or every implementation of the present disclosure. Furtherfeatures and advantages are disclosed in the embodiments that follow.The Drawings and the Detailed Description that follow more particularlyexemplify certain embodiments using the principles disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate generally, by way of example, but not by way oflimitation, various embodiments discussed in the present document.

FIG. 1 is a perspective view of an abrasive article according to oneexample of the present disclosure.

FIG. 2 is a side cross-sectional view of abrasive articles according tovarious embodiments of the present disclosure.

FIG. 3 is a schematic showing the step-wise construction of abrasivearticles according to various embodiments of the present disclosure.

FIGS. 4A-4I are side cross-sectional views of a portion of an abrasivearticle according to various embodiments of the present disclosure.

FIGS. 5-7 are side cross-sectional views of abrasive articles accordingto embodiments of the present disclosure.

FIG. 8 is a close-up view of an abrasive article made with heatactivated adhesive according to embodiments of the present disclosure.

FIG. 9 is a schematic illustration of a method of making an abrasivearticle with heat activated adhesive according to embodiments of thepresent disclosure.

FIG. 10 is a method of making an abrasive article using heat activatedadhesive according to embodiments of the present disclosure.

FIGS. 11A-11C illustrate steps in a method of making an abrasive articleusing heat activated adhesive according to embodiments of the presentdisclosure.

FIGS. 12A-12B illustrate close-up views of abrasive articles made withheat activated adhesive according to embodiments of the presentdisclosure.

FIGS. 13-15 illustrate examples of another method of making an abrasivearticle with shaped agglomerate abrasive structures according toembodiments of the present disclosure.

FIG. 16 illustrates a schematic of an abrasive article according toembodiments of the present disclosure.

FIGS. 17A-F illustrates coated abrasive articles according toembodiments of the present disclosure.

FIG. 18 illustrates a method of making coated abrasive articlesaccording to embodiments of the present disclosure.

FIG. 19 illustrates coated abrasive articles described in the Examples.

It should be understood that numerous other modifications and examplescan be devised by those skilled in the art, which fall within the scopeand spirit of the principles of the disclosure. Figures may not be drawnto scale.

DESCRIPTION

Embodiments described herein are directed to an abrasive article thatnot only retains the dust-extraction advantages of an abrasive on anet-type backing, but also demonstrates abrasive performance (cut and/orlife) advantages of a conventional abrasive. This combination ofbenefits (dust extraction and cut and/or life) is possible because theconstruction of the abrasive articles described herein allows forpattern-coating abrasive on a fabric backing to form well-defined areasof abrasive coating as well as open areas devoid of any abrasivecoating. The patterned abrasive area can therefore be designedindependent of any pattern present on the fabric substrate, to optimizeboth abrasive performance and dust extraction. Embodiments herein alsoapply to direct coating of abrasive articles, particularly net-typebacked abrasive articles.

FIG. 1 is a perspective view of one example of an abrasive articlereferred to by the numeral 100. As shown, the abrasive article 100includes: a fabric substrate 110 comprising strands forming first voidspaces 270 between the strands (see FIG. 2 ); and an abrasive layer 120joined to the fabric substrate 110; abrasive particles joined to theresin; and a plurality of void spaces extending through the fabricsubstrate 110 and the abrasive layer. The plurality of void spacescoinciding with void spaces in the fabric substrate 110 allow for an airflow through the article 100 at a rate of, e.g., at least 0.1 L/s (e.g.at least 0.2 Us, at least 0.4 L/s, at least 0.6 L/s, at least 1 L/s; orabout 0.1 L/s to about 1 L/s, about 0.25 Us to about 0.75 L/s, about 0.5L/s to about 1 L/s, about 1 L/s to about 2 L/s, about 1.5 L/s or about 3L/s), such that, when in use, dust can be removed from an abradedsurface through the abrasive article.

FIG. 1 illustrates one example of an abrasive article with large voidspaces, according to PCT Application with Ser. No. 2020/050984, filed onFeb. 11, 2020, incorporated herein by reference. Said applicationdiscusses the benefits of a laminate, as illustrated in FIG. 1 . Onesuch benefit of a laminate layer for a mesh backing is the prevention ofbleed-through of the make resin to the attachment side of the abrasivearticle. However, methods and articles described herein illustrate thatbleed-through can be avoided without a laminate layer. As describedherein, it is possible to prevent bleed-through by treating anattachment side of the mesh with a hydro-lipophobic treatment that canrepel the make coat, allowing for a continuous surface to form on theabrasive side.

FIG. 1 shows a relatively simple pattern that can be created with theabrasive layers 120. But the conceivable patterns are many. For example,abrasive articles 100 having various patterns in the abrasive layer 120are shown in PCT Application with Ser. No. 2020/050984, filed on Feb.11, 2020. As can be seen, the abrasive layers 120 can comprise aplurality of pattern elements 121, which may or may not be repeatedacross the surface of the abrasive article 100. Each pattern element 121can be comprised of one or more sub-elements. Different pattern elements121 within the same abrasive article may be provided with the same ordifferent abrasive particles 250 or other additives (for example,different abrasive grades, blends of abrasive particles 250, fillers,grinding aids, etc.) as desired for a given application. Although thearticles depicted are presented in the form of circular discs, it shouldbe understood that abrasive articles could take any form (for example,sheets or belts).

FIG. 2 shows a cross-section of an abrasive article referred to by thenumeral 100 taken on the line 2-2 of FIG. 1 looking in the direction ofthe arrows. As shown in FIG. 2 , the abrasive article 100 includes: afabric substrate 110 comprising strands 260 forming first void spaces270 between the strands 260; a hydro-lipophobic coating 230 joined tothe fabric substrate 110 on an attachment side of substrate 110. A curedresin composition 240 (e.g., the cured product of a phenolic resin) isjoined on the opposite side of the fabric substrate 110 from thehydro-lipophobic coating; abrasive particles 250 joined to the curedresin composition 240; and a plurality of second void spaces 280extending through the coating and the make coat, coinciding with firstvoid spaces 270 in the fabric substrate 110.

The abrasive particles 250 are at least partially embedded in the curedresin composition 240. As used herein, the term “at least partiallyembedded” generally means that at least a portion of an abrasiveparticle is embedded in the cured resin composition, such that, theabrasive particle is anchored in the cured resin composition. In someembodiments, abrasive particles 250 are coated in the form of a slurrycomposition. Abrasive particles 250 can optionally be oriented byinfluence of a magnetic field prior to the resin 240A being cured. See,for example, commonly-owned PCT Pub. Nos. 2018/080703, 2018/080756,2018/080704, 2018/080705, 2018/080765, 2018/080784, 2018/136271,2018/134732, 2018/080755, 2018/080799, 2018/136269, 2018/136268. In someother embodiments, abrasive particles 250 can optionally be placed usingtools for controlled orientation and placement of abrasive particles.See, for example, commonly-owned PCT Pub. Nos. 2012/112305, 2015/100020,2015/100220, 2015/100018, 2016/028683, 2016/089675, 2018/063962,2018/063960, 2018/063958, 2019/102312, 2019/102328, 2019/102329,2019/102330, 2019/102331, 2019/102332, 2016/205133, 2016/205267,2017/007714, 2017/007703, 2018/118690, 2018/118699, 2018/118688, U.S.Pat. Pub. No. 2019-0275641, and U.S. Provisional Pat. Appl. Nos.62/751,097, 62/767,853, 62/767,888, 62/780,987, 62/780,988, 62/780,994,62/780,998, 62/781,009, 62/781,021, 62/781,037, 62/781,043, 62/781,057,62/781,072, 62/781,077, 62/781,082, 62/825,938, 62/781,103.

Making reference to FIG. 2 , the abrasive article 100 comprises a firstside 210 and a second side 212 opposite the first side 210. The secondside 212 can include one part of a two-part hook and loop attachmentsystem 213. The first side can include the abrasive particles within orembedded on a make resin layer. Bleed-through is prevented, in someembodiments, by coating the first side with a hydro-lipophobic coatinglayer that prevents the make resin from bleeding through, as discussedin greater detail below.

FIG. 3 shows an example of one method by which the abrasive article 100shown in FIG. 1 can be constructed in step-wise fashion.

In a first step, a hydro-lipophobic coating layer is applied to fabricsubstrate 110 comprising strands 260 forming first void spaces 270between the strands 260. The hydro-lipophobic coating can be applied tothe fabric substrate 110 by any suitable means, including a plasmatreatment, a spray coating, or a foam, such as a fluoro-chemical basedfoam.

In a second step, uncured resin composition 240A is joined to the fabricsubstrate 110 on a side opposite the hydro-lipophobic coating layer. Theuncured resin composition 240A can be applied in any suitable methodincluding by using a (rotary) stencil/screen printing roll, flatbedscreen/stencil printing or by directly printing the uncured resincomposition 240A onto the fabric substrate or by using combinations oftwo or more suitable methods (e.g., extrusion die coating, curtaincoating, knife coating, gravure coating, and spray coating) for joiningthe uncured resin composition 240A to the fabric substrate 110.

In a third step, abrasive particles 250 are joined to the uncured resincomposition 240A by any suitable method, including drop, patternelectrostatic, magnetic, and other mechanical methods of mineralcoating. For example, abrasive particles 250 can be deposited ontouncured resin composition 240A by simply dropping the abrasive particles250 onto the uncured resin composition 240A; by electrostaticallydepositing abrasive particles 250 onto the uncured resin composition240A; or by using combinations of two or more suitable methods forjoining the abrasive particles 250 to the uncured resin composition240A. In some embodiments, the abrasive particles 250 can optionally beoriented under the influence of a magnetic field prior to the resin 240Abeing cured, as earlier indicated. The abrasive particles 250 may alsobe pattern coated on the uncured or partially cured resin composition.

In a fourth step, the uncured resin composition 240A is cured, this wayabrasive particles 250 are at least partially embedded in the curedresin composition 240 and are substantially permanently attached.Uncured resin composition 240A can be cured to form cured resin 240 byany applicable curing mechanism, including thermal cure, photochemicalcure, moisture-cured or combinations of two or more curing mechanism.But if the uncured resin composition 240A is cured by any means thatdoes not include heating, a fifth step (not shown) may be necessary tofully open the void spaces 270 between strands 260.

During the curing process, at least a portion of cured resin composition240 migrates away from the first void spaces 270 between strands 260,thereby opening a plurality of second void spaces 280 coinciding withfirst void spaces 270. Cured resin composition 240 is absent above thefirst void spaces 270. Although FIG. 3 shows an example of one method bywhich the abrasive article 100 shown in FIG. 1 can be constructed instep-wise fashion, methods are also contemplated where one or more ofthe steps described herein can be accomplished in a single step orwherein certain steps can be performed in an order different than whatis shown in FIG. 3 .

In step 1, a coating 230 is applied to a first side of substrate 110.First side may be an attachment side including, for example, one part ofa hook and loop attachment system. The coating may be a hydrophobiccoating, for embodiments where the resin to be applied is a water-basedresin. The coating may be a lipophobic coating, for embodiments wherethe resin to be applied is an organic-based resin. The hydro-lipophobiccoating can be applied as a plasma treatment, for example. Thehydrophobic coating may include fluorinated compounds, in someembodiments. The coating, in some embodiments, is a low-surface-energycoating features both hydrophobic and lipophobic features. The coatingmay be a fluorochemical coating, a silane coating, a silicone coating,or nano-surface treatment.

In step 2, make resin is applied to a second side of the substrate. Makeresin may be pattern coated, as illustrated in FIG. 3 .

In step 3, abrasive particles 250 are coupled to the make resin.

FIGS. 4A-4I show the various permutations (not exhaustive) that canoccur when the cured resin composition 240 is coated or otherwisemigrates away from the first void spaces 270 between strands 260. Forexample, the cured resin 240 can at least partially wrap around thestrands 260 to create second void spaces 280, thus leaving open thefirst void spaces 270 as shown in FIGS. 4B, 4D, 4F, 4G, 4H, and 4I. Insuch instances, the resin composition 240 extends over only the strands260, not over first void spaces 270. And in some instances, the resincomposition 240 can wrap around some stands 260 and not others, as shownin FIG. 4I.

FIG. 5 shows one example of an abrasive article referred to by thenumeral 200, which incorporates all of the features shown in FIG. 1 ,which will not be discussed again for the sake of brevity, but also asize coat 510 having size coat void spaces 520, which coincide withsecond void spaces 280. FIG. 6 shows one example of an abrasive articlereferred to by the numeral 300, which incorporates all of the featuresshown in FIG. 5 , which will not be discussed again for the sake ofbrevity, but also a supersize coat 610 having supersize coat void spaces620, which coincide with size coat void spaces 520 and second voidspaces 280.

The layer configurations described herein are not intended to beexhaustive, and it is to be understood that layers can be added orremoved with respect to any of the examples depicted in FIGS. 1-3 .

The abrasive article of the various embodiments described herein includefabric substrate 110. Fabric substrate 110 may be constructed from anyof a number of materials known in the art for making coated abrasivearticles. Although not necessarily so limited, fabric substrate 110 canhave a thickness of at least 0.02 millimeters, at least 0.03millimeters, 0.05 millimeters, 0.07 millimeters, or 0.1 millimeters. Thebacking could have a thickness of up to 5 millimeters, up to 4millimeters, up to 2.5 millimeters, up to 1.5 millimeters, or up to 0.4millimeters.

Fabric substrate 110 can be flexible and has voids spaces (e.g., voidspaces 270 between strands 260) such that it is porous. Flexiblematerials from which fabric substrate 110 can be made include cloth(e.g., cloth made from fibers or yarns comprising polyester, nylon,silk, cotton, and/or rayon, which may be woven, knit or stitch bonded)and scrim. The fabric substrate 110 can comprise a loop backing.

The abrasive layer of the abrasive article of the various embodimentsdescribed herein is made from a curable composition (e.g., uncured orpartially cured resin composition 240A). In some instances, therefore,this specification makes reference to cured (e.g., cured resincomposition 240) or uncured compositions (e.g., uncured or partiallycured resin composition 240A), where the cured composition is synonymouswith the abrasive layer 120.

The nature of the uncured or partially cured resin composition 240A thatis converted to cured resin composition 240 is non-limiting, and caninclude, for example, any suitable additives or formulations describedin PCT Application with Ser. No. IB2020/050984, filed Feb. 7, 2020.

In some embodiments, the curable compositions can contain one or morefiber reinforcement materials. The use of a fiber reinforcement materialcan provide an abrasive layer having improved cold flow properties,limited stretchability, and enhanced strength. Preferably, the one ormore fiber reinforcement materials can have a certain degree of porositythat enables a photoinitiator, when present, to be dispersed throughout,to be activated by UV light, and properly cured without the need forheat. Further options and advantages of the fiber reinforcementmaterials are described in U.S. Patent Publication No. 2002/0182955(Weglewski et al.).

While resin-based methods have been described thus far for attachingabrasive particles to a nonwoven abrasive article, it is also expresslycontemplated that other methods may be possible. For example, FIGS. 8-12illustrate another embodiment of the present invention in which aheat-activated adhesive is used to attach abrasive particles to a fiberbacking.

FIG. 8 is a close-up view of an abrasive article made with heatactivated adhesive according to embodiments of the present disclosure.FIG. 8 illustrates a mesh abrasive 1100 with a mesh backing 1110 ontowhich a heat activated adhesive 1120 has been applied. The heatactivated adhesive can be applied on a nonwoven web and used to adhereabrasive particles without the use of an additional resin material. Inone embodiment, an adhesive with a melting point above 170° is used.However, in other embodiments, adhesives with lower melting points canbe used. The adhesive should have a melting point high enough that theadhesive will not melt during use of an abrasive article.

FIG. 9 is a schematic illustration of a method of making an abrasivearticle with heat activated adhesive according to embodiments of thepresent disclosure. Schematic images 1201A and 1251A illustrate a sideview of backing showing the loops as attached to a single fiber.Schematic images 1201B and 1251B illustrate front views of three fibersin a mesh backing. While schematic images 1201A-B and 1251A-B illustrateonly a few fibers 1230 for ease of understanding, it is understood thatthe concept applies to larger arrangements of fibers 1230.

A plurality of fibers 1230, each with one or more attached loops 1220,can be coated with a heat activated adhesive 1240. In one embodiment aheat activated adhesive film 1240 is laminated to fibers 1230. Adhesivefilm 1240 can be heated to a melting temperature, to ensure adhesion tofibers 1230, and cooled back down to room temperature. Abrasiveparticles 1210 can be applied to adhesive film 1240. For example,abrasive particles 1210 may be heated to a temperature high enough tosoften adhesive film 1240, allowing abrasive particles 1210 to embedwithin adhesive layer 1240, as illustrated in schematic images 1251A and1251B. Adhesive particles that do not attach to adhesive layer 1240 mayfall through the voids in the fiber backing, as illustrated in FIG.1251B.

While crushed abrasive particles are illustrated in FIG. 9 , it isexpressly contemplated that the method illustrated can be applied toother abrasive particles, such as platey, formed, shaped, or partiallyshaped particles.

FIG. 10 is a method of making an abrasive article using heat activatedadhesive according to embodiments of the present disclosure. Method 1300may be useful for making abrasive articles.

In block 1310, a heat activated adhesive is applied to a backing. In oneembodiment, the backing is a mesh backing. Applying a heat activatedadhesive to a backing can include laminating the adhesive as a film, asindicated in block 1302, or directly coating the adhesive, as indicatedin block 1304, or roll-coating the adhesive, as indicated in block 1306.Other application methods may also be used, as indicated in block 1308.Applying a heat-activated adhesive to a backing may also involve firstheating the adhesive layer, as indicated in block 312, and then coolingthe adhesive layer, as indicated in block 314.

In block 1320, abrasive grains are applied to the adhesive backing.Applying adhesive grains to the adhesive layer can include drop-coatingmethods, as indicated in block 1322, using a transfer tool, as indicatedin block 1324, or other methods, as indicated in block 1326. Forexample, magnetically coated abrasive particles may be aligned on anadhesive-coated backing by applying a magnetic force. Additionally,abrasive particles may be coated using electrostatic forces.

The abrasive grains can be embedded into the adhesive layer by partiallymelting the heat-activated adhesive. This can be done by pre-heating theabrasive grains to a temperature higher than the melting point of theheat-activated adhesive, as indicated in block 1327. The potentialcooling of the abrasive particles during transfer to the adhesive shouldbe considered. Therefore, in some embodiments, the abrasive grains areheated to a temperature several degrees higher than the melting point toallow for cooling during the coating process. The adhesive-coatedbacking can be heated, either in addition to or as an alternative toheating the abrasive particles, as indicated in block 1328.

In block 1330, additives are applied. For example, multiple types ofabrasive grains can be applied to the adhesive layer, as indicated inblock 1332. For example, both precision shaped grains and crushed grainsmay be adhered to the adhesive layer. Alternatively, two different sizesof precision shaped grains may be applied to the adhesive layer.Additional functional layers may also be applied over the adheredabrasive grains, such as a size coat, as indicated in block 1334, or asupersize coat, as indicated in block 1336. Additional layers may alsobe included, as indicated in block 1338, such as a grinding aid orlubrication aid.

FIGS. 11A-11C illustrate steps in a method of making an abrasive articleusing heat activated adhesive according to embodiments of the presentdisclosure. FIG. 11A illustrates a mesh backing 1400 with a plurality offibers 1410. FIG. 11B illustrates a mesh backing 1450 where a heatactivated adhesive 1420 has been applied to portions of fibers 1410 ofmesh backing 1450. FIG. 11C illustrates a mesh backing 1480 coated withprecision-shaped abrasive particles 1430. The precision-shaped particles1430 of FIG. 11C are triangle-shaped, however other shapes are alsoexpressly envisioned for other embodiments.

FIGS. 12A-12B illustrate close-up views of abrasive articles made withheat activated adhesive according to embodiments of the presentdisclosure. FIG. 12A illustrates a view of a mesh backing coated withP100 aluminum-zirconia abrasive particles. FIG. 12B illustrates a meshbacking coated with precision-shaped grain that was applied by heatingthe mesh backing to 155° C. before drop-coating the particles. However,it is also expressly contemplated that the particles, instead of or inaddition to the mesh backing, could be pre-heated before application.

A wide variety of abrasive particles may be utilized in the variousembodiments described herein. The particular type of abrasive particle(e.g. size, shape, chemical composition) is not considered to beparticularly significant to the abrasive article, so long as at least aportion of the abrasive particles are suitable for the intended end-useapplication. Suitable abrasive particles may be formed of, for example,cubic boron nitride, zirconia, alumina, silicon carbide and diamond.

The abrasive particles may be provided in a variety of sizes, shapes andprofiles, including, for example, random or crushed shapes, regular(e.g. symmetric) profiles such as square, star-shaped or hexagonalprofiles, and irregular (e.g. asymmetric) profiles.

The abrasive article may include a mixture of abrasive particles thatare inclined on the backing (i.e. stand upright and extend outwardlyfrom the backing) as well as abrasive particles that lie flat on theirside (i.e. they do not stand upright and extend outwardly from thebacking).

The abrasive article may include a mixture of different types ofabrasive particles. For example, the abrasive article may includemixtures of platey and non-platey particles, crushed, agglomerated, andshaped particles (which may be discrete abrasive particles that do notcontain a binder or agglomerate abrasive particles that contain abinder), conventional non-shaped and non-platey abrasive particles (e.g.filler material) and abrasive particles of different sizes.

Examples of different types of agglomerate based abrasive articles on amesh backing can be seen in FIGS. 13-15 . FIGS. 13A-13D illustrateabrasive agglomerate particles on a mesh backing. As illustrated in FIG.13A, an agglomerate abrasive particle 1700 includes abrasive grains 1710and can have one or more agglomerate shape features. Agglomerateabrasive particle 1700, as illustrated in FIG. 13A, may also include asecond type of abrasive particle 1720.

In one embodiment, abrasive agglomerate 1700 can be defined as having awidth, w, a thickness, h, with a ratio of w/h being higher than 2. In apreferred embodiment, the width is higher than 5. In some embodiments,the width of the agglomerate is larger than 1000 μm. The abrasiveagglomerates, as illustrated in FIGS. 13A-13D may be at least partiallyprecisely shaped. The shapes may include, but are not limited to,nonagon, octagon, heptagon, hexagon, triangle (scalene, acute, obtuse,isosceles, equilateral, or right), parallelogram, rhombus, rectangle,square, pentagon, circle, oval, heart, cross, arrow, star (with anynumber of points from 3, as illustrated in FIG. 13A, to 10), orcrescent.

Abrasive agglomerate particles such as those illustrated in FIGS.13A-13D may be especially useful for making mesh abrasive articles. Asillustrated in FIG. 13B, at least one dimension of the abrasive particle1700 is greater than the gaps in mesh backing 1750, ensuring thatabrasive agglomerates do not fall through the mesh backing.

As illustrated in FIGS. 13C and 13D, abrasive agglomerate particles 1760may comprise abrasive particles 1764 within a resin bond 1762. Theabrasive agglomerate particles may be placed on a backing 1750 in apattern, or dropped in a random configuration. This can give the benefitof a ‘patterned’ abrasive structure, as each individual agglomerate hasa shape, but also the benefits of random placement, which may reducescratches or cut patterns on an abraded worksurface. Additionally,systems and methods herein can also apply to direct coating methods ofabrasives and resins.

FIG. 14 illustrates one schematic method of making a mesh abrasivearticle with agglomerate abrasive particles. The agglomerates 1830 maybe premade, for example, using methods of making agglomerates describedin U.S. PAP 2019/0283216, published on Sep. 19, 2019 and U.S. PAP2017/058254 (describing vitrified shaped agglomerates), and PCTPublication WO 2019/0167022, published Sep. 6, 2019 (describingsiliceous bond agglomerates), as well as US PAP 2019/0270922, publishedSep. 5, 2019, all of which are incorporated herein by reference. Oncemade, the agglomerates may proceed, as indicated in direction 1850, on aconveyance mechanism 1840. While a horizontal conveyance mechanism 1840is illustrated, it is expressly contemplated that a tilted conveyancemechanism 1840, or other suitable deposition mechanisms, such as a dropcoater or other suitable mechanism for depositing the agglomerates 1830in a pattern or random configuration.

A backing 1810 proceeds, also in direction 1850 in one embodiment, on aconveyance mechanism. Backing 1810 may have a make coat 1820 appliedsuch that deposited abrasive agglomerates 1830. Make coat 1820 mayinclude a make resin, a blown melty film, or a hot melt adhesive, forexample.

FIGS. 15A and 15B illustrate linear abrasive agglomerates that may alsobe useful in mesh abrasive article formation. As illustrated in FIG.15B, the linear abrasive agglomerate has at least one dimension that islonger than a gap between mesh fibers, ensuring that the abrasiveagglomerate will adhere to a make resin layer on the abrasive article.

Examples of suitable shaped abrasive particles can be found in, forexample, U.S. Pat. No. 5,201,916 (Berg) and U.S. Pat. No. 8,142,531(Adefris et al.) A material from which the shaped abrasive particles maybe formed comprises alpha alumina. Alpha alumina shaped abrasiveparticles can be made from a dispersion of aluminum oxide monohydratethat is gelled, molded to shape, dried to retain the shape, calcined,and sintered according to techniques known in the art.

Examples of suitable shaped abrasive particles can also be found inPublished U.S. Appl. No. 2015/0267097, which is incorporated herein byreference. Published U.S. Appl. No. 2015/0267097 generally describesabrasive particles comprising alpha alumina having an average crystalgrain size of 0.8 to 8 microns and an apparent density that is at least92 percent of the true density. Each shaped abrasive particle can have arespective surface comprising a plurality of smooth sides that form atleast four vertexes.

U.S. Pat. No. 8,034,137 (Erickson et al.) describes alumina abrasiveparticles that have been formed in a specific shape, then crushed toform shards that retain a portion of their original shape features. Insome embodiments, shaped alpha alumina particles are precisely-shaped(i.e., the particles have shapes that are at least partially determinedby the shapes of cavities in a production tool used to make them).Details concerning such shaped abrasive particles and methods for theirpreparation can be found, for example, in U.S. Pat. No. 8,142,531(Adefris et al.); U.S. Pat. No. 8,142,891 (Culler et al.); and U.S. Pat.No. 8,142,532 (Erickson et al.); and in U.S. Pat. Appl. Publ. Nos.2012/0227333 (Adefris et al.); 2013/0040537 (Schwabel et al.); and2013/0125477 (Adefris).

Examples of suitable crushed abrasive particles include crushed abrasiveparticles comprising fused aluminum oxide, heat-treated aluminum oxide,white fused aluminum oxide, ceramic aluminum oxide materials such asthose commercially available as 3M CERAMIC ABRASIVE GRAIN from 3MCompany, St. Paul, Minn., brown aluminum oxide, blue aluminum oxide,silicon carbide (including green silicon carbide), titanium diboride,boron carbide, tungsten carbide, titanium carbide, diamond, cubic boronnitride, garnet, fused alumina zirconia, iron oxide, chromia, zirconia,titania, tin oxide, quartz, feldspar, flint, emery, sol-gel-derivedceramic (e.g., alpha alumina), and combinations thereof. Furtherexamples include crushed abrasive composites of abrasive particles(which may be platey or not) in a binder matrix, such as those describedin U.S. Pat. No. 5,152,917 (Pieper et al.).

Examples of sol-gel-derived abrasive particles from which crushedabrasive particles can be isolated, and methods for their preparationcan be found in U.S. Pat. No. 4,314,827 (Leitheiser et al.); U.S. Pat.No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,744,802 (Schwabel),U.S. Pat. No. 4,770,671 (Monroe et al.); and U.S. Pat. No. 4,881,951(Monroe et al.). It is also contemplated that the crushed abrasiveparticles could comprise abrasive agglomerates such as, for example,those described in U.S. Pat. No. 4,652,275 (Bloecher et al.) or U.S.Pat. No. 4,799,939 (Bloecher et al.).

The crushed abrasive particles comprise ceramic crushed abrasiveparticles such as, for example, sol-gel-derived polycrystalline alphaalumina particles. Ceramic crushed abrasive particles composed ofcrystallites of alpha alumina, magnesium alumina spinel, and a rareearth hexagonal aluminate may be prepared using sol-gel precursor alphaalumina particles according to methods described in, for example, U.S.Pat. No. 5,213,591 (Celikkaya et al.) and U.S. Publ. Pat. Appln. Nos.2009/0165394 A1 (Culler et al.) and 2009/0169816 A1 (Erickson et al.).

Further details concerning methods of making sol-gel-derived abrasiveparticles can be found in, for example, U.S. Pat. No. 4,314,827(Leitheiser); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No.5,435,816 (Spurgeon et al.); U.S. Pat. No. 5,672,097 (Hoopman et al.);U.S. Pat. No. 5,946,991 (Hoopman et al.); U.S. Pat. No. 5,975,987(Hoopman et al.); and U.S. Pat. No. 6,129,540 (Hoopman et al.); and inU.S. Patent Publication No. 2009/0165394 A1 (Culler et al.). Examples ofsuitable platey crushed abrasive particles can be found in, for example,U.S. Pat. No. 4,848,041 (Kruschke).

The abrasive particles may be surface-treated with a coupling agent(e.g., an organosilane coupling agent) or other physical treatment(e.g., iron oxide or titanium oxide) to enhance adhesion of the crushedabrasive particles to the binder.

The abrasive layer, in some embodiments, includes a particulate mixturecomprising a plurality of formed abrasive particles (e.g., precisionshaped grain (PSG) mineral particles available from 3M, St. Paul, Minn.,which are described in greater detail herein; not shown in FIGS. 1-3 )and a plurality of abrasive particles 250, or only formed abrasiveparticles, adhesively secured to the abrasive layer.

In some embodiment, the abrasive particles may be formed abrasiveparticles. As used herein, the term “formed abrasive particles”generally refers to abrasive particles (e.g., formed ceramic abrasiveparticles) having at least a partially replicated shape. Non-limitingexamples of formed abrasive particles are disclosed in Published U.S.Patent Appl. No. 2013/0344786, which is incorporated by reference as iffully set forth herein. Non-limiting examples of formed abrasiveparticles include shaped abrasive particles formed in a mold, such astriangular plates as disclosed in U.S. Pat. Nos. RE 35,570; U.S. Pat.Nos. 5,201,916, and 5,984,998 all of which are incorporated by referenceas if fully set forth herein; or extruded elongated ceramicrods/filaments often having a circular cross section produced bySaint-Gobain Abrasives an example of which is disclosed in U.S. Pat. No.5,372,620, which is incorporated by reference as if fully set forthherein. Formed abrasive particle as used herein excludes randomly sizedabrasive particles obtained by a mechanical crushing operation.

Formed abrasive particles also include shaped abrasive particles. Asused herein, the term “shaped abrasive particle,” generally refers toabrasive particles with at least a portion of the abrasive particleshaving a predetermined shape that is replicated from a mold cavity usedto form the shaped precursor abrasive particle. Except in the case ofabrasive shards (e.g. as described in U.S. patent publication US2009/0169816), the shaped abrasive particle will generally have apredetermined geometric shape that substantially replicates the moldcavity that was used to form the shaped abrasive particle. Shapedabrasive particle as used herein excludes randomly sized abrasiveparticles obtained by a mechanical crushing operation.

Formed abrasive particles also include precision-shaped grain (PSG)mineral particles, such as those described in Published U.S. Appl. No.2015/267097, which is incorporated by reference as if fully set forthherein.

Examples of suitable abrasive particles include, for example, fusedaluminum oxide, heat treated aluminum oxide, white fused aluminum oxide,black silicon carbide, green silicon carbide, titanium diboride, boroncarbide, silicon nitride, tungsten carbide, titanium carbide, diamond,cubic boron nitride, hexagonal boron nitride, garnet, fused aluminazirconia, alumina-based sol gel derived abrasive particles, silica, ironoxide, chromia, ceria, zirconia, titania, tin oxide, gamma alumina, andmixtures thereof. The alumina abrasive particles may contain a metaloxide modifier. The diamond and cubic boron nitride abrasive particlesmay be monocrystalline or polycrystalline.

In some examples, the formed abrasive particles have a substantiallymonodisperse particle size of from about 1 micrometers to about 5000micrometers, from about 1 micrometers to about 2500, from about 1micrometers to about 1000, from about 10 micrometers to about 5000, fromabout 10 micrometers to about 2500, from about 10 micrometers to about1000, from about 50 micrometers to about 5000, from about 50 micrometersto about 2500, from about 50 micrometers to about 1000. As used herein,the term “substantially monodisperse particle size” is used to describeformed abrasive particles having a size that does not varysubstantially. Thus, for example, when referring to formed abrasiveparticles (e.g., a PSG mineral particles) having a particle size of 100micrometers, greater than 90%, greater than 95% or greater than 99% ofthe formed abrasive particles will have a particle having its largestdimension be 100 micrometers.

In some embodiments, the abrasive particles can have a range ordistribution of particle sizes. Such a distribution can be characterizedby its median particle size. For instance, the median particle size ofthe abrasive particles may be at least 0.001 micrometers, at least 0.005micrometers, at least 0.01 micrometers, at least 0.015 micrometers, orat least 0.02 micrometers. In some instances, the median particle sizeof the abrasive particles may be up to 300 micrometers, up to 275micrometers, up to 250 micrometers, up to 150 micrometers, or up to 100micrometers. In some examples, the median particle size of the abrasiveparticles is from about 1 micrometers to about 600 micrometers, fromabout 1 micrometers to about 300 micrometers, from about 1 micrometersto about 150 micrometers, from about 10 micrometers to about 600micrometers, from about 10 micrometers to about 300 micrometers, fromabout 10 micrometers to about 150 micrometers, from about 50 micrometersto about 600 micrometers, from about 50 micrometers to about 300micrometers, from about 50 micrometers to about 150 micrometers.

In some examples, the abrasive particle of the present disclosure mayinclude formed abrasive particles. The formed abrasive particles may bepresent from 0.01 wt. percent to 100 wt, percent, from 0.1 wt. percentto 100 wt, percent, from 1 wt. percent to 100 wt, from 10 wt. percent to100 wt, percent, from 0.01 wt. percent to 90 wt, percent, from 0.1 wt.percent to 90 wt, percent, from 1 wt. percent to 90 wt, from 10 wt.percent to 90 wt, percent, from 0.01 wt. percent to 75 wt, percent, from0.1 wt. percent to 75 wt, percent, from 1 wt. percent to 75 wt, from 10wt. percent to 75 wt, percent, based on the total weight of the abrasiveparticles.

In some examples, the particulate mixture comprises from about greaterthan 90 wt. % to about 99 wt. % abrasive particles (e.g., from about 91wt. % to about 97 wt. %; about 92 wt. % to about 97 wt. %; about 95 wt.% to about 97 wt. %; or greater than about 90 wt. % to about 97 wt. %).

In some embodiments, the abrasive article of the various embodimentsdescribed herein include a size coat 510. See FIG. 5 . In some examples,the size coat comprises the cured product of a phenolic sizecomposition. In other examples, the size coat comprises the cured (e.g.,photopolymerized) product of a bis-epoxide (e.g., 3,4-epoxycyclohexylmethyl-3,4-epoxy cyclohexylcarboxylate, available from DaicelChemical Industries, Ltd., Tokyo, Japan); a trifunctional acrylate(e.g., trimethylol propane triacrylate, available under the tradedesignation “SR351” from Sartomer USA, LLC, Exton, Pa.); an acidicpolyester dispersing agent (e.g., “BYK W-985” from Byk-Chemie, GmbH,Wesel, Germany); a filler (e.g., a sodium-potassium alumina silicatefiller, obtained under the trade designation “MINEX 10” from The CaryCompany, Addison, Ill.); a photoinitiator (e.g., a triarylsulfoniumhexafluoroantimonate/propylene carbonate photoinitiator, obtained underthe trade designation “CYRACURE CPI 6976” from Dow Chemical Company,Midland, Mich.; and an α-Hydroxyketone photoinitiator, obtained underthe trade designation “DAROCUR 1173” from BASF Corporation, FlorhamPark, N.J.).

In some embodiments, the abrasive article of the various embodimentsdescribed include a supersize coat 610. See FIG. 6 . In general, thesupersize coat is the outermost coating of the abrasive article anddirectly contacts the workpiece during an abrading operation. Thesupersize coat is, in some examples, substantially transparent.

The term “substantially transparent” as used herein refers to a majorityof, or mostly, as in at least about 30%, 40%, 50%, 60%, or at leastabout 70% or more transparent. In some examples, the measure of thetransparency of any given coat described herein (e.g., the supersizecoat) is the coat's transmittance. In some examples, the supersize coatdisplays a transmittance of at least 5 percent, at least 20 percent, atleast 40 percent, at least 50 percent, or at least 60 percent (e.g., atransmittance from about 40 percent to about 80 percent; about 50percent to about 70 percent; about 40 percent to about 70 percent; orabout 50 percent to about 70 percent), according to a Transmittance Testthat measures the transmittance of 500 nm light through a sample of 6 by12 inch by approximately 1-2 mil (15.24 by 30.48 cm by 25.4-50.8 μm)clear polyester film, having a transmittance of about 98%.

One component of supersize coats can be a metal salt of a long-chainfatty acid (e.g., a C₁₂-C₂₂ fatty acid, a C₁₄-C₁₈ fatty acid, and aC₁₆-C₂₀ fatty acid). In some examples, the metal salt of a long-chainfatty acid is a stearate salt (e.g., a salt of stearic acid). Theconjugate base of stearic acid is C₁₇H₃₅COO—, also known as the stearateanion. Useful stearates include, but are not limited to, calciumstearate, zinc stearate, and combinations thereof.

The metal salt of a long-chain fatty acid can be present in an amount ofat least 10 percent, at least 50 percent, at least 70 percent, at least80 percent, or at least 90 percent by weight based on the normalizedweight of the supersize coat (i.e., the average weight for a unitsurface area of the abrasive article). The metal salt of a long-chainfatty acid can be present in an amount of up to 100 percent, up to 99percent, up to 98 percent, up to 97 percent, up to 95 percent, up to 90percent, up to 80 percent, or up to 60 percent by weight (e.g., fromabout 10 wt. % to about 100 wt. %; about 30 wt. % to about 70 wt. %;about 50 wt. % to about 90 wt. %; or about 50 wt. % to about 100 wt. %)based on the normalized weight of the supersize coat.

Another component of the supersize coat is a polymeric binder, which, insome examples, enables the supersize coat to form a smooth andcontinuous film over the abrasive layer. In one example, the polymericbinder is a styrene-acrylic polymer binder. In some examples, thestyrene-acrylic polymer binder is the ammonium salt of a modifiedstyrene-acrylic polymer, such as, but not limited to, JONCRYL® LMV 7051.The ammonium salt of a styrene-acrylic polymer can have, for example, aweight average molecular weight (Mw) of at least 100,000 g/mol, at least150,000 g/mol, at least 200,000 g/mol, or at least 250,000 g/mol (e.g.,from about 100,000 g/mol to about 2.5×106 g/mol; about 100,000 g/mol toabout 500,000 g/mol; or about 250,000 to about 2.5×106 g/mol).

The minimum film-forming temperature, also referred to as MFFT, is thelowest temperature at which a polymer self-coalesces in a semi-dry stateto form a continuous polymer film. In the context of the presentdisclosure, this polymer film can then function as a binder for theremaining solids present in the supersize coat. In some examples, thestyrene-acrylic polymer binder (e.g., the ammonium salt of astyrene-acrylic polymer) has an MFFT that is up to 90° C., up to 80° C.,up to 70° C., up to 65° C., or up to 60° C.

In some examples, the binder is dried at relatively low temperatures(e.g., at 70° C. or less). The drying temperatures are, in someexamples, below the melting temperature of the metal salt of along-chain fatty acid component of the supersize coat. Use ofexcessively high temperatures (e.g., temperatures above 80° C.) to drythe supersize coat is undesirable because it can induce brittleness andcracking in the backing, complicate web handling, and increasemanufacturing costs. By virtue of its low MFFT, a binder comprised of,e.g., the ammonium salt of a styrene-acrylic polymer allows thesupersize coat to achieve better film formation at lower binder levelsand at lower temperatures without need for added surfactants such asDOWANOL® DPnP.

The polymeric binder can be present in an amount of at least 0.1percent, at least 1 percent, or at least 3 percent by weight, based onthe normalized weight of the supersize coat. The polymeric binder can bepresent in an amount of up to 20 percent, up to 12 percent, up to 10percent, or up to 8 percent by weight, based on the normalized weight ofthe supersize coat. Advantageously, when the ammonium salt of a modifiedstyrene acrylic copolymer is used as a binder, the haziness normallyassociated with a stearate coating is substantially reduced.

The supersize coats of the present disclosure optionally contain clayparticles dispersed in the supersize coat. The clay particles, whenpresent, can be uniformly mixed with the metal salt of a long chainfatty acid, polymeric binder, and other components of the supersizecomposition. The clay can bestow unique advantageous properties to theabrasive article, such as improved optical clarity and improved cutperformance. The inclusion of clay particles can also enable cutperformance to be sustained for longer periods of time relative tosupersize coats in which the clay additive is absent.

The clay particles, when present, can be present in an amount of atleast 0.01 percent, at least 0.05 percent, at least 0.1 percent, atleast 0.15 percent, or at least 0.2 percent by weight based on thenormalized weight of the supersize coat. Further, the clay particles canbe present in an amount of up to 99 percent, up to 50 percent, up to 25percent, up to 10 percent, or up to 5 percent by weight based on thenormalized weight of the supersize coat.

The clay particles may include particles of any known clay material.Such clay materials include those in the geological classes of thesmectites, kaolins, illites, chlorites, serpentines, attapulgites,palygorskites, vermiculites, glauconites, sepiolites, and mixed layerclays. Smectites in particular include montmorillonite (e.g., a sodiummontmorillonite or calcium montmorillonite), bentonite, pyrophyllite,hectorite, saponite, sauconite, nontronite, talc, beidellite, andvolchonskoite. Specific kaolins include kaolinite, dickite, nacrite,antigorite, anauxite, halloysite, indellite and chrysotile. Illitesinclude bravaisite, muscovite, paragonite, phlogopite and biotite.Chlorites can include, for example, corrensite, penninite, donbassite,sudoite, pennine and clinochlore. Mixed layer clays can includeallevardite and vermiculitebiotite. Variants and isomorphicsubstitutions of these layered clays may also be used.

As an optional additive, abrasive performance may be further enhanced bynanoparticles (i.e., nanoscale particles) interdispersed (e.g., in theclay particles) in the supersize coat. Useful nanoparticles include, forexample, nanoparticles of metal oxides, such as zirconia, titania,silica, ceria, alumina, iron oxide, vanadia, zinc oxide, antimony oxide,tin oxide, and alumina-silica. The nanoparticles can have a medianparticle size of at least 1 nanometer, at least 1.5 nanometers, or atleast 2 nanometers. The median particle size can be up to 200nanometers, up to 150 nanometers, up to 100 nanometers, up to 50nanometers, or up to 30 nanometers.

Other optional components of the supersize composition include curingagents, surfactants, antifoaming agents, biocides, and other particulateadditives known in the art for use in supersize compositions.

The supersize coat can be formed, in some examples, by providing asupersize composition in which the components are dissolved or otherwisedispersed in a common solvent. In some examples, the solvent is water.After being suitably mixed, the supersize dispersion can be coated ontothe underlying layers of the abrasive article and dried to provide thefinished supersize coat. If a curing agent is present, the supersizecomposition can be cured (e.g., hardened) either thermally or byexposure to actinic radiation at suitable wavelengths to activate thecuring agent.

The coating of the supersize composition onto, e.g., the abrasive layercan be carried out using any known process. In some examples, thesupersize composition is applied by spray coating at a constant pressureto achieve a pre-determined coating weight. Alternatively, a knifecoating method where the coating thickness is controlled by the gapheight of the knife coater can be used.

FIG. 16 illustrates schematic views of a strand 2020 within a coatedabrasive article 2000. A single strand 2020 has a make coat 2030deposited on one side, to which abrasive particles 2040 are adhered. Inone embodiment, a fabric substrate 202 has an attachment system, such aslooks 2010, adhered to a side opposing the abrasive particles.

Abrasive articles can be made using fabric substrates with strands, suchas strand 2020 of FIG. 16 , in an open weave, with large openingsseparating adjoining strands. Applying a standard make resin 2030 isdifficult on an open backing without complex coating equipment orprocess. Systems and methods are desired to allow placement of makeresin 2030 on an open mesh backing 2020 using knife or roller coating.

One problem with applying traditional coating methods to an open meshbacking is the force of gravity 2050 applied on the make coat 2030during application and curing, causing make coat 2030 to bleed throughbacking 2020 and onto the loop attachment system 2010. This caninterfere with attachment system 2010 functionally coupling article 2000to an abrading system.

In some embodiments described herein, a coating or treatment is appliedto a backing of an abrasive article to induce partial, temporary, orpermanent hydro-lipophobicity that can reduce the surface energy of thebackside of the backing and prevent the make resin from wicking thebackside of the backing and the sidewalls of individual strands withinthe backing. Hydrophobicity is desired for make resins that are at leastpartially aqueous in nature. Lipophobic is desired for make resins thatare at least partially lipid in nature. A hydro-lipophobic coating canbe applied using a variety of materials, including, for example,tetramethylsilane, titanium oxide, or using a treatment a fluorine basedfunctional group, such as Perfluorobutanesulfonic acid (such asScotchgard® from 3M) or a treatment with a perfluoroalkyl group (such asAG-E500D from Mitsubishi®). In some embodiments, a wax coating wouldalso be suitable, however was may be susceptible to wetting by epoxy orsome liquid resins.

FIG. 17A-D illustrate coated abrasive articles made with ahydro-lipophobic coating applied to an attachment side of a backingprior to a make coat being applied on an abrasive side of the backing.FIG. 17A illustrates a mesh backing 2100 coated with a make resin 2110.FIG. 17B illustrates a mesh backing 2100 with precision shaped abrasiveparticles 2120 adhered to a make coat on the mesh backing. FIG. 17Cillustrates a mesh backing 2100 with crushed abrasive grains 2130 coatedon a make resin. FIG. 17D illustrates a view of the back 2160 of theabrasive article of FIG. 17C. As illustrated, there is substantially nomake coat bleeding through onto the attachment side of the backing.Loops 2140 and backside 2150 of mesh are substantially free of makeresin.

FIGS. 17E and 17F illustrate a comparative backing coated with a makeresin without an applied hydrophobic coating. FIG. 17E illustrates acoated side 2170 and FIG. 17F illustrates a loop side 2180. Asillustrated, make resin has permeated through from the coated side 2170to loop side 2180.

FIG. 18 illustrates a method of making a coated abrasive article. Method2200 may allow for more efficient and cheaper manufacturing of coatedabrasive articles on open substrates, such as an open mesh backing.

In block 2210, a loop side coating is applied to a backing substrate.The loop side coating is a hydrophobic coating 2202, for example, suchas tetramethyl silane, titanium oxide, or treatment with a fluorinatedcompound. Another treatment 2206 may also be applied. For example, aplasma treatment may be used to make a loop-side of a backinghydrophobic. The hydrophobic coating applied in block 2210 may be atemporary coating that dissipates over time or is otherwise removedduring use, in one embodiment. In another embodiment, the hydrophobiccoating is a layer applied to the backing that is maintained throughmanufacturing and abrading of a workpiece using the coated abrasivearticle.

In block 2220, a make coat is applied to the abrasive side of thebacking, opposite the hydrophobic coated side of the backing. The makecoat may be a resin coating 2212 or a hot melt adhesive coating 2214, asdescribed herein. Applying a make coat may also comprise applying aseparate laminate coating layer 2216, as described herein. The laminatelayer may be a blown melty film 2218, or another coating layer 2222.

The make coat may be applied using a roll coating method, as illustratedin block 2224, or using a knife coating method, as illustrated in block2226. Other suitable methods may also be used, as illustrated in block2228.

The hydrophobic coating on the loop side of the backing prevents themake coat, when applied to the backing, from bleeding through thesubstrate and onto the loop side. In some embodiments, the loop side ofthe backing is substantially free of make coat.

In block 2230, abrasive particles are applied to the make layer. Theabrasive particles may be shaped abrasive particles 2231, crushedabrasive particles, 2232, agglomerates 2234, or other particles 2236 asdescribed herein. The abrasive particles may embed within the make resinand thus adhere to the backing.

Additional coating layers may also be applied to the adhered particles,including a size coat, a supersize coat, grinding aid or additionalfunctional layers.

The term “about” as used herein can allow for a degree of variability ina value or range, for example, within 10%, within 5%, or within 1% of astated value or of a stated limit of a range.

Unless specified otherwise herein, the term “substantially” as usedherein refers to a majority of, or mostly, as in at least about 50%,60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or atleast about 99.999% or more.

Unless specified otherwise herein, the term “substantially no” as usedherein refers to a minority of, or mostly no, as in less than about 10%,5%, 2%, 1%, 0.5%, 0.01%, 0.001%, or less than about 0.0001% or less.

Values expressed in a range format should be interpreted in a flexiblemanner to include not only the numerical values explicitly recited asthe limits of the range, but also to include all the individualnumerical values or sub-ranges encompassed within that range as if eachnumerical value and sub-range were explicitly recited. For example, arange of “about 0.1% to about 5%” or “about 0.1% to 5%” should beinterpreted to include not just about 0.1% to about 5%, but also theindividual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g.,0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range.The statement “about X to Y” has the same meaning as “about X to aboutY,” unless indicated otherwise. Likewise, the statement “about X, Y, orabout Z” has the same meaning as “about X, about Y, or about Z,” unlessindicated otherwise.

In this document, the terms “a,” “an,” or “the” are used to include oneor more than one unless the context clearly dictates otherwise. The term“or” is used to refer to a nonexclusive “or” unless otherwise indicated.In addition, it is to be understood that the phraseology or terminologyemployed herein, and not otherwise defined, is for the purpose ofdescription only and not of limitation. Any use of section headings isintended to aid reading of the document and is not to be interpreted aslimiting. Further, information that is relevant to a section heading mayoccur within or outside of that particular section. Furthermore, allpublications, patents, and patent documents referred to in this documentare incorporated by reference herein in their entirety, as thoughindividually incorporated by reference. In the event of inconsistentusages between this document and those documents so incorporated byreference, the usage in the incorporated reference should be consideredsupplementary to that of this document; for irreconcilableinconsistencies, the usage in this document controls.

In the methods described herein, the steps can be carried out in anyorder without departing from the principles of the invention, exceptwhen a temporal or operational sequence is explicitly recited.Furthermore, specified steps can be carried out concurrently unlessexplicit claim language recites that they be carried out separately. Forexample, a claimed step of doing X and a claimed step of doing Y can beconducted simultaneously within a single operation, and the resultingprocess will fall within the literal scope of the claimed process.

Select embodiments of the present disclosure include, but are notlimited to, the following: An abrasive article is presented thatincludes a fabric substrate comprising strands forming first void spacesbetween the strands, the fabric substrate comprising an abrasive sideand an attachment side. The abrasive article also includes a coating onthe attachment side, and a make layer joined to the fabric substrate onthe abrasive side, and abrasive particles joined to the make layer. Theabrasive article also includes a plurality of second void spacesextending through the make layer coinciding with first void spaces inthe fabric substrate. The coating on the fabric substrate reduces thesurface energy and features both hydrophobic and lipophobic properties.The attachment side of the fabric substrate is substantially free ofmake layer.

The abrasive article may be implemented such that the coated attachmentside includes one part of a two-part hook and loop attachment system.

The abrasive article may be implemented such that the fabric substratecomprises a woven or knitted material.

The abrasive article may be implemented such that the abrasive particlescomprise shaped abrasive particles.

The abrasive article may be implemented such that the abrasive particlescomprise agglomerate abrasive particles, and wherein the agglomerateabrasive particles comprise shaped abrasive particles.

The abrasive article may be implemented such that the agglomerateabrasive particles are shaped agglomerate abrasive particles, andwherein the shape comprises an nonagon, an octagon, a heptagon, ahexagon, a triangle, a parallelogram, a rhombus, a rectangle, a square,a pentagon, a circle, an oval, a heart, a cross, an arrow, a star, or acrescent.

The abrasive article may be implemented such that the agglomerateabrasive particles are arranged in a pattern on the fabric substrate.

The abrasive article may be implemented such that the agglomerateabrasive particles are arranged randomly on the fabric substrate.

The abrasive article may be implemented such that air flows through thearticle at a rate of at least 0.5 L/s, such that, when in use, dust canbe removed from an abraded surface through the abrasive article.

The abrasive article may be implemented such that the make coatcomprises a resin or a hot melt.

The abrasive article may be implemented such that the coating comprisesapplying a plasma treatment in a hydrophobic and lipophobic atmosphere.

The abrasive article may be implemented such that the plasma treatmentcomprises a fluorochemical or a silane.

The abrasive article may be implemented such that the coating comprisesa hydrophobic and lipophobic chemical.

The abrasive article may be implemented such that the chemical is afluorinated compound, a silane or a silicone.

The abrasive article may be implemented such that the coating comprisesnanoparticles.

The abrasive article may be implemented such that the nanoparticles aresilica nanoparticles or carbon nanotubes.

The abrasive article may be implemented such that it includes a sizecoat.

The abrasive article may be implemented such that it includes asupersize coat.

The abrasive article may be implemented such that the supersize coat isa stearate coating.

A method of making an abrasive article is presented that includescoating an attachment side of a fabric substrate with a hydrophobiccoating material, joining a make layer composition to the fabricsubstrate on an abrasive side of the fabric substrate and joiningabrasive particles to the make layer composition. The fabric substratecomprises strands forming first void spaces between the strands.

The method may be implemented such that it also includes curing thecurable resin composition to provide a cured resin composition.

The method may be implemented such that it also includes the curingcreates a plurality of second void spaces coinciding with first voidspaces in the fabric substrate.

The method may be implemented such that the abrasive particles compriseagglomerate abrasive particles, and wherein the agglomerate abrasiveparticles comprise shaped abrasive particles.

The method may be implemented such that the agglomerate abrasiveparticles are shaped agglomerate abrasive particles, and wherein theshape comprises an nonagon, an octagon, a heptagon, a hexagon, atriangle, a parallelogram, a rhombus, a rectangle, a square, a pentagon,a circle, an oval, a heart, a cross, an arrow, a star, or a crescent.

The method may be implemented such that joining the abrasiveagglomerates to the curable resin composition comprises depositing theabrasive agglomerates in a pattern.

The method may be implemented such that joining the abrasiveagglomerates to the curable resin composition comprises depositing theabrasive agglomerates randomly.

The method may be implemented such that the make coat comprises a resinor a hot melt.

The method may be implemented such that the coating comprises a plasmatreatment.

The method may be implemented such that the coating comprises afluorinated compound.

The method may be implemented such that it also includes joining a sizelayer composition to the abrasive particle layer.

The method may be implemented such that it also includes joining asupersize layer composition to the size layer.

An abrasive article is presented that includes a fabric substratecomprising a plurality of strands forming first void spaces between thestrands, an adhesive layer comprising adhesive bonded to the pluralityof strands and abrasive particles embedded within the adhesive layer.

The abrasive article may be implemented such that the adhesive layercomprises a heat activated adhesive.

The abrasive article may be implemented such that the abrasive particlesare crushed abrasive particles, platey abrasive particles, formedabrasive particles, shaped abrasive particles, or partially shapedabrasive particles.

The abrasive article may be implemented such that the abrasive particlescomprise agglomerate abrasive particles, and wherein the agglomerateabrasive particles comprise shaped abrasive particles.

The abrasive article may be implemented such that the agglomerateabrasive particles are shaped agglomerate abrasive particles, andwherein the shape comprises an nonagon, an octagon, a heptagon, ahexagon, a triangle, a parallelogram, a rhombus, a rectangle, a square,a pentagon, a circle, an oval, a heart, a cross, an arrow, a star, or acrescent.

The abrasive article may be implemented such that the abrasiveagglomerates are embedded in the adhesive layer in a pattern.

The abrasive article may be implemented such that the abrasiveagglomerates are embedded in the adhesive layer randomly.

The abrasive article may be implemented such that the adhesive layer isbonded to the plurality of strands on an adhesive side of the fabricsubstrate, and wherein, on an attachment side, the fabric substrate iscoated with a hydrophobic coating.

The abrasive article may be implemented such that the hydrophobiccoating comprises a plasma treatment.

The abrasive article may be implemented such that the hydrophobiccoating comprises fluorinated compound.

A method of making an abrasive article is presented that includesapplying a hydrophobic coating to an attachment side of a fabricsubstrate and applying an adhesive layer to an abrasive side of thefabric substrate. The fabric substrate comprises strands forming firstvoid spaces between the strands. The adhesive layer is applied such thatadhesive adheres substantially only to the strands and does notsubstantially extend into the void spaces. The method also includesapplying a plurality of abrasive particles to the adhesive layer suchthat the abrasive particles are partially embedded within the adhesivelayer.

The method may be implemented such that the adhesive layer comprises aheat activated adhesive.

The method may be implemented such that applying an adhesive layercomprises laminating the fabric substrate with an adhesive layer.

The method may be implemented such that it also includes heating theadhesive layer.

The method may be implemented such that applying the plurality ofabrasive particles comprises drop-coating the abrasive particles.

The method may be implemented such that the abrasive particles areheated.

The method may be implemented such that the adhesive layer is heated.

The method may be implemented such that it also includes applying a sizecoat.

The method may be implemented such that it also includes applying asupersize coat.

The method may be implemented such that the abrasive particles compriseagglomerate abrasive particles. The agglomerate abrasive particlescomprise shaped abrasive particles.

The method may be implemented such that the agglomerate abrasiveparticles are shaped agglomerate abrasive particles, and wherein theshape comprises an nonagon, an octagon, a heptagon, a hexagon, atriangle, a parallelogram, a rhombus, a rectangle, a square, a pentagon,a circle, an oval, a heart, a cross, an arrow, a star, or a crescent.

The method may be implemented such that applying the abrasiveagglomerates to the adhesive layer comprises depositing the abrasiveagglomerates in a pattern.

The method may be implemented such that applying the abrasiveagglomerates to the adhesive layer comprises depositing the abrasiveagglomerates randomly.

Examples

The examples described herein are intended solely to be illustrative,rather than predictive, and variations in the manufacturing and testingprocedures can yield different results. All quantitative values in theExamples section are understood to be approximate in view of thecommonly known tolerances involved in the procedures used. The foregoingdetailed description and examples have been given for clarity ofunderstanding only. No unnecessary limitations are to be understoodtherefrom.

Unless stated otherwise, all reagents were obtained or are availablefrom chemical vendors such as Sigma-Aldrich Company, St. Louis, Mo., ormay be synthesized by known methods. Unless otherwise reported, allratios are by dry weight.

Unit Abbreviations used in the Examples: gsm=grams per square meter;cm=centimeter; μm=micron.

Materials used in the Examples are reported in Table 1, below:

TABLE 1 MESH Net Mesh GR150 H100 (150 gsm) with loops knitted on oneside available from SitiP, S.p.A., Cene, Italy. PFR1 Phenol-formaldehyderesin having a phenol to formaldehyde molar ratio of 1:1.5-2.1, andcatalyzed with 2.5 percent by weight potassium hydroxide. PRR2Water-based phenol-formaldehyde resin supplied by Georgia- PacificChemicals LLC, Atlanta, GA, with 75% solid. CACO Calcium carbonatecommercially available as HUBERCARB Q325 from Hubercarb EngineeredMaterials, Atlanta Georgia. RED Red synthetic iron oxide pigmentsupplied by Venator Americas LLC, The Woodlands, TX, under the trademarkKROMA ®. Interwet Surfactant supplied by Valtris Specialty Chemicals,Walton Hills, OH. SIL Silicon Dioxide Cabosil M5 from ET HORN CO, LaMirada California. MKR1 Phenolic make resin 1, prepared by mixing 55parts by weight of PFR, 44.5 parts by weight of CACO, and 0.5 parts byweight of SIL. MKR2 Phenolic make resin 2, prepared by mixing 97.2 partsby weight of PFR2, 1 parts by weight of water, 1.6 parts by weight ofRED, and 0.2 parts by weight of Interwet. MKR3 Phenolic make resin 2,prepared by mixing 50.5 parts by weight of PFR2, 40 parts by weight ofCACO, 1.6 parts by weight of RED, 7.7 parts by weight of water, and 0.2parts by weight of Interwet. SAP Shaped abrasive particles, preparedaccording to the disclosure of U.S. Pat. No. 8,142,531 (Adefris et al.).The SAP used in the examples were about 200 μm (side length) × 50 μm(thickness), with a draft angle approximately 98 degrees. AOP Fused andfired Aluminum oxide particles of size P180, produced by Triebacher,Austria SiC Silicon Carbide abrasive mineral supplied by Jiangsu LeyuanNew Materials Group Co., Ltd, Lianyungang City, China. SLU Slurry,prepared by mixing 39.5 parts by weight of PFR, 0.5 parts by weight ofSIL, 12 parts by weight of SAP, and 48 parts by weight of AOP.

A. Plasma-Treatment Examples

A sheet of MESH of about 22.9 cm×22.9 cm were mounted on the poweredelectrode of Reactor One with the loop side facing up to the chamberatmosphere. The reactor chamber was pumped down to a base pressure ofless than 1.3 Pa (10 mTorr). Then tetramethylsilane (TMS, available as aliquid from Aldrich Chemical Company, Milwaukee, Wis.) was introducedinto the chamber at a flow rate of 25 standard cubic centimeters perminute (sccm). When the TMS flow was established, oxygen (O₂, availablein gas cylinders from Oxygen Service Company, Minneapolis, Minn.) wasmetered into the chamber at a flow rate of 500 sccm. The total chamberpressure was 23.9 Pa (180 mTorr). Then, a plasma was ignited with radiofrequency (RF) power of 450 watts. An ion sheath formed around thepowered electrode, extended approximately 10-15 mm outward and thusencompassed the porous article. Plasma treatment was continued for twominutes. After extinguishing the plasma, the gas flows were stopped, thechamber pressure brought down to below 10 mTorr, after which the chamberwas vented to atmosphere. Details related to plasma processing andoperation can be found in U.S. Pat. No. 6,878,419 (David et al.)Multiple sheets were treated by repeating this process.

The first abrasive example was prepared with abrasive particles onlycoated on the raised yarns of the coat side of the plasma-treated MESH:MKR was roll coated on the coat side of a treated MESH as mentionedabove with about 76 μm controlled gap, and followed by drop coat of 4grams of SAP on the top of MKR. Then the abrasive sample was put in ovenfor resin cure.

The second abrasive example was prepared with pattern-coated abrasiveslurry on the coat side of the plasma-treated MESH: a 0.15 mm thickhexagon-patterned stencil, which has staggered hexagons as open areaswith 2 mm of side and adjacent distance, was put on the top of the coatside of a treated MESH as mentioned above. All the edges were tapedtightly to the MESH to ensure there was no space between the stencil andmesh web. Then SLU was coated through the stencil using a rubbersqueegee. The stencil was removed after coating, and the abrasive samplewas put in oven for resin cure.

Creating Hydrophobicity on Loop Side with Hydrophobic Coating

A composition comprising 0.2 g AG-E500D (ASAHI GUARD E-SERIES AG-E500D,30%, from AGC Chemicals Americas Inc. Exton, Pa.), 1.0 g sodiumcarboxymethyl cellulose (CMC, average Mw 90K, Sigma-Aldrich Company),20.0 g hexanes (98.5% from Sigma-Aldrich Company), and 78.0 g water wasblended with a high speed shearer (IKA EUROSTAR 200 Overhead Stirrer,IKA Works, Inc. Wilmington, N.C.) at a speed of 1500 rpm for 20 min toform a temporary stable foam solution.

The foam solution was applied onto the loop side of the MESH backingwith a knife coater with the add-on of 11.8 g on 250 square centimetersarea. The sample was dried at 80 C for 5 minutes and then cured at 105 Cfor 1 minute. Optionally, the treated MESH backing was rinsed with 60 Cwater and then dried at 105 C for 1 minute.

Making Coated MESH Abrasive Articles Comprising SAP

MKR2 was applied to the non-loop side of the treated MESH backing withknife coating. Pressurized air was then applied from the loop side toopen the pores on the MESH backing. P150 grade SAP was drop coated ontothe make resin and then the sample was dried at 90 C for 60 minutes.

MKR2 on treated MESH backing is illustrated in FIG. 17A.

P150 SAP coated on MESH backing is illustrated in FIG. 17B.

Making Coated MESH Abrasive Articles Comprising SiC

The same procedure was used except that MR3 and P220 grade SiC was used.P220 grade SiC coated on the MESH backing is illustrated in FIG. 17C,with a backside illustrated in FIG. 17D.

COMPARATIVE EXAMPLE

For comparative purposes, on a piece of MESH backing with the size of23×28 cm, half of the MESH backing was treated with hydrophobic coatingand half of the backing remain untreated. MKR2 was applied onto thenon-loop side of the backing with knife coater. Due to the repellentproperty of the treated loop side, the make resin can only sit on thenon-loop side of the MESH backing. On the untreated MESH backing, themake resin wicked through the MESH backing and contaminated the loopside of the MESH backing. The result is illustrated in FIG. 19 .

1. An abrasive article comprising: a fabric substrate comprising strandsforming first void spaces between the strands, the fabric substratecomprising an abrasive side and an attachment side; a coating on theattachment side; a make layer joined to the fabric substrate on theabrasive side; abrasive particles joined to the make layer; a pluralityof second void spaces extending through the make layer coinciding withfirst void spaces in the fabric substrate; and wherein the coating onthe fabric substrate reduces the surface energy and features bothhydrophobic and lipophobic properties, and wherein the attachment sideof the fabric substrate is substantially free of make layer.
 2. Theabrasive article of claim 1, wherein the coated attachment side includesone part of a two-part hook and loop attachment system.
 3. The abrasivearticle of claim 1, wherein the fabric substrate comprises a woven orknitted material.
 4. The abrasive article of claim 1, wherein theabrasive particles comprise shaped abrasive particles. 5-7. (canceled)8. The abrasive article of claim 1, wherein the make coat comprises aresin or a hot melt.
 9. The abrasive article of claim 1, wherein thecoating comprises applying a plasma treatment in a hydrophobic andlipophobic atmosphere.
 10. (canceled)
 11. The abrasive article of claim1, wherein the coating comprises a hydrophobic and lipophobic chemical.12. The abrasive article of claim 1, wherein the chemical is afluorinated compound, a silane or a silicone.
 13. The abrasive articleof claim 1, wherein the coating comprises nanoparticles. 14-17.(canceled)
 18. A method of making an abrasive article comprising:coating an attachment side of a fabric substrate with a hydrophobiccoating material; joining a make layer composition to the fabricsubstrate on an abrasive side of the fabric substrate; and joiningabrasive particles to the make layer composition; wherein the fabricsubstrate comprises strands forming first void spaces between thestrands.
 19. The method of claim 18, and further comprising curing thecurable resin composition to provide a cured resin composition and,wherein the curing creates a plurality of second void spaces coincidingwith first void spaces in the fabric substrate. 20-23. (canceled) 24.The method of claim 18, wherein the make coat comprises a resin or a hotmelt.
 25. The method of claim 18, wherein the coating comprises a plasmatreatment.
 26. The method of claim 18, wherein the coating comprises afluorinated compound.
 27. (canceled)
 28. An abrasive article comprising:a fabric substrate comprising a plurality of strands forming first voidspaces between the strands; an adhesive layer comprising adhesive bondedto the plurality of strands; and abrasive particles embedded within theadhesive layer.
 29. The abrasive article of claim 28, wherein theadhesive layer comprises a heat activated adhesive.
 30. The abrasivearticle of claim 28, wherein the abrasive particles comprise agglomerateabrasive particles, and wherein the agglomerate abrasive particlescomprise shaped abrasive particles.
 31. The abrasive article of claim28, wherein the adhesive layer is bonded to the plurality of strands onan adhesive side of the fabric substrate, and wherein, on an attachmentside, the fabric substrate is coated with a hydrophobic coating.
 32. Theabrasive article of claim 31, wherein the hydrophobic coating comprisesa plasma treatment.
 33. The abrasive article of claim 31, wherein thehydrophobic coating comprises fluorinated compound. 34-40. (canceled)